The present invention relates to a fiber optic cable system. More specifically, the present invention relates to a fiber optic cable system that avoids potential damage to the cladding and/or coating of a fiber optic ribbon by controlling the placement of adhesives and epoxies.
Fiber optic systems generally accommodate the transmission of optical signals from a light-emitting diode (LED) laser or some other light source to a receiver, such as a photodiode, wavelength-division multiplexing (WDM) component, and the like. When transmitted, optical signals travel through optical cables. These cables are generally constructed of a glass or plastic material and generally have three parts; the core, the cladding and the coating. The core is the center portion of the cable having a higher index of refraction for light transmission. The cladding material is positioned between the core and the coating. The cladding has a lower index of refraction than the core to provide complete internal reflection and encourage light transmission through the core. Without the cladding, light gradually leaks out of the core. As a further protection measure, the coating covers the cladding. The coating is generally a soft, flexible material that protects the fiber from damage.
Fiber optic systems are typically made up of numerous optical components, all communicating via fiber optic cables. As anticipated, the use of quality connections makes these systems operate efficiently. Thus, connectors of many different types are very important to achieve efficient and effective system performance. For example, long distance fiber optic systems may require signal regenerators, signal repeaters, or optical amplifiers in order to maintain signal quality.
In such systems, the quality of the light signal can also be decreased when the cladding and coating materials that protect the core of a fiber optic cable are damaged. While many potential sources for damage exist, one known source is the initial placement of the connector on the fiber optic cable. Additionally, damage may often occur during the mating, unmating and remating of the connectors. In other circumstances, optical systems are subject to high motion environments (i.e., high shock and/or vibration), which creates additional stress on the connectors or cables, and another potential source for damage.
There are several different types of connectors used for fiber-to-fiber connections, including FC, fiber distributed data interface (FDDI), LC, MT Array, subscription channel (SC), SC Duplex and straight tip (ST) connectors. These different types of connectors are used in varying applications based upon their unique performance and overall characteristics. Most fiber-to-fiber connectors have the same four, basic components, however, including a ferrule, a connector body, a cable and a coupling device. The ferrule is a fiber alignment mechanism with a bore generally at the center having a diameter slightly larger than the fiber cladding. The connector body generally holds the ferrule such that the ferrule extends beyond the length of the connector body to slip into a coupling device. The connector body is typically attached to strengthening members or cable jackets via crimping or bonding. Connector bodies are generally alignment sleeves know as feed-through, bulk head adapters. In most instances, a strain relief boot is added at the cable and connector interface to provide extra protection at this junction. The coupling device is attached the exposed portion of the ferrule extending away from the connector body.
In order to achieve an efficient and effective connection, certain steps must be followed when attaching the fiber optic connector to the fiber optic cable. As is understood, the quality of the light signal passing through the connection can be negatively impacted by defects at the end of the fiber cable, dirt or other impurities coating the fiber cable, or deformities in the cladding and coating. Some connector manufacturers provide connector kits to help eliminate or minimize these problems associated with attaching the fiber optic connector to the fiber optic cable.
In the attachment of the fiber optic cables to their related ferrule, various epoxies are traditionally used. These epoxies have strong bonding characteristics but are very rigid once they are cured. Obvious problems are created when these types of rigid epoxies are applied to portions of the connector where flexibility is desired and often necessary. More specifically, these problems include separation of the cladding from the core and damage to the outer coating of the fiber optic cable. In addition to these problems, epoxy making unwanted rigid connections between the cable and the strain relief boot are also undesirable because flexibility would be greatly reduced.
When epoxy is applied between the fiber optic cable and the ferrule, it will often seep or wick into any open voids or holes. As the opening in the ferrule does not precisely match the shape of the fiber optic cable, the potential for seepage always exists. Again, wicking or seepage to undesired locations creates a potential for future cable damage.
Despite efforts by connector manufacturers to standardize and simplify fiber optic connectors, there still exists a need for improved protection of fiber optic connectors. In addition, there exists a need for sealing mechanisms that protect the components of the connector from excessive adhesive wicking without negatively impacting the quality of the optical signal. There also exists a need for a fiber optic cable connector that allows for the termination of more than one fiber optic cable in one connector where the connector is sized to receive a plurality of fiber optic cables, often more than actually used. Having the ability to attach such connectors greatly expands the system capabilities and provides flexibility for the designer. Overall, there is a need to have connectors where the components of the connector are securely adhered to each other without degrading the coating and cladding of the cables or the optic signal.